Sleep occupies about one-third of our life and is necessary for mental and physical well-being. It additionally affects mood, behavior and physiology. Sleep and the control of sleep is a complex process involving multiple neuro-chemical pathways and associated brain structures. It is a dynamic process involving a shift in the balance of distinct physiological changes, involving both positive and negative signaling neural signaling. The regulation of sleep in humans is governed by three processes—each influenced by hormonal and environmental factors: a daily sleep-wake cycle influenced by a circadian rhythm (24 hour cycle) tied to light-dark cycles.
The need for sleep is a biological drive similar to thirst or hunger. Interestingly though, the function of sleep is largely unknown, however some evidence indicates that sleep is required for learning. In North America, insomnia is estimated to affect a significant portion of the population every year and is associated with health problems and concomitant economic loss to society (Stoller M K. Economic effects of insomnia. Clin Ther. 1994 September-October;16(5):873-97 Abstract). It is clear that the impairment of sleep is detrimental to one's health. In humans, mild sleep deprivation results in indications of impaired immune system function (Irwin M, McClintick J, Costlow C, Fortner M, White J, Gillin J C. Partial night sleep deprivation reduces natural killer and cellular immune responses in humans. FASEB J. 1996 April;10(5):643-53.). Prolonged sleep deprivation is even known to result in death. It has been determined by many that an individual can survive longer without food than one can without sleep; thus indicating the importance of sleep.
Strategies to improve sleep are beneficial, not only in terms of physical health, but also in terms of emotional health. Furthermore, reinforcement of sleep of adequate quantity and quality positively impacts most aspect of daily life.